1. Field of the Invention
The present invention relates to a time switching device having identical frame delay in a full-electronic exchange and method therefor, and more particularly to a time switching device having identical frame delay in a full-electronic exchange and method therefor, wherein only a single time memory within the time switching device is utilized for switching multichannel in the full-electronic exchange to allow respective channels to have identical frame delay, thereby providing data service of the channel capacity larger than 64[Kbps].
2. Description of the Prior Art
In order to make respective channels have identical frame delay in a time switch after switching the multichannel, a time memory having a capacity twice the time switch capacity is generally utilized to divide the time memory into two address areas, and access is carried out alternatively to the two address areas by one frame period (i.e., 125 .mu.s) during performance of a memory write and read operations.
However, the memory write and read operations performed by means of the time having a capacity twice the time switch capacity can be accomplished only when the frame pulse position of the input side is identical to that of the output side of the time memory. If the time switch includes a multiplexer and a backward multiplexer, data becomes multiplexed while the pulse position of a frame, i.e., a starting point of a time slot, is determined to be supplied to the time memory. Therefore, the output positions differ in response to a random read address, so that the identical frame delay of respective channels cannot be secured after switching the multichannel.
Accordingly, in order to solve this problem, a conventional time switch is separately attached to a time memory for adjusting the frame position to permit the frame pulse positions of the input side and output side of the time memory to be identical to each other, thereby making it possible to provide the multichannel service. In this case, however, system structure is complicated due to addition of the separate time memory, causing inconvenience in constructing the system.
In connection with the time switch, a technique described in U.S. Pat. No. 4,995,034 is known to the person of ordinary skill in the art, in which the construction of a telecommunication system is simplified and, simultaneously, a specific portion can be expanded without additionally installing a switch. More specifically, in a telecommunication system including a plurality of user terminals, a module for providing at least one accessory function, and a central switch for providing time division multiplex communication between the above two devices, at least one fixed time slot is assigned to establish mutual communication of the user terminals, and the assigned time slot is utilized to execute mutual access. Successively, the assigned time slot is divided into a plurality of telecommunication channels, and a part of the plurality of telecommunication channels is selected to establish the mutual communication in the module that provides the accessory function.
Consequently, the above technique is contrived to solve a problem of additionally installing the separate switch, which results from employing the accessory-function providing module that requires the plurality of channels, thereby reducing the burdensome cost. However, a single memory is used as the time memory portion within the time switch of the switch to carry out the inherent function, which cannot be applied to a technique for simplifying the system structure.